The Modbus Holding Register is configured as follows:

1. Go to the settings panel of the Modbus Holding Register object that is created on the basis of the Modbus Device object.
   

2. In the Address field, enter the Holding Register address in the register map of this device.

   The registers map is provided by the manufacturer. The register address is always less than the register number by 1. The register address is specified in the settings.

   
   

3. Set the Poll checkbox to start polling the Modbus Holding Register. This makes the settings available for editing.
4. From the Rule drop-down list, select the Modbus rule to which this Holding Register complies (see Configuring the Modbus Rule).
5. Set the Skip 'value changed' event checkbox, so that the Event Viewer window doesn't display the events of Holding Register value change.
6. Set the Skip indicator feature checkbox to disable the display of the Holding Register value on the map in text form.
   

   Сhange of this parameter is applied after you restart the ACFA PSIM Server.

7. Set the Skip rule-configured events checkbox, so that the Event Viewer window doesn't display the events of rule triggering.
8. From the Interpretation drop-down list, select the Holding Register data format:
   • Two bytes,
   • Two bytes (signed),
   • Four bytes,
   • Four bytes (signed),
   • Four bytes (floating),
   • Eight bytes,
   • Eight bytes (signed),
   • Eight bytes (floating).
9. To add a numeric operation to the table, click the  button.
   

   To delete a numeric operation from the table, click the  button. You can change the sequences of operations using the following buttons: to move up one position, click the  button, to move down one position, click the  button.

10. From the list of operations, select:
    
    
    1. Reverse. Select from the available options:
       • Entirely, byte by byte,
       • Entirely, bit by bit,
       • Bits in byte,
       • Bits in words,
       • Bytes in words,
       • Bytes in double words,
       • By words (per 2 bytes),
       • Bits in double words,
       • By double words (per 4 bytes). 

    2. Shift.
       In the Shift operation settings window:
       

       1. From the Direction drop-down list, select in which direction the Holding Register value is shifted: Left (default) or Right.
       2. In the Count field, specify how many bits are shifted. The default value is 1.
       3. Click the OK button to save the settings.
    3. Mask.
       In the Mask operation settings window:
       
       
       1. From the Mode drop-down list, select the logical operator AND (default), OR, or XOR. 
       2. Specify the bitmask value in decimal (DEC) or hexadecimal (HEX) format, or set the corresponding checkboxes. 
       3. Click the OK button to save the settings.
11. Click the Apply button to save the settings.

The Modbus Holding Register is now configured.